Platform: Code4rena
Start Date: 29/04/2022
Pot Size: $22,000 USDC
Total HM: 6
Participants: 40
Period: 3 days
Judge: Justin Goro
Total Solo HM: 2
Id: 114
League: ETH
Rank: 36/40
Findings: 1
Award: $28.35
🌟 Selected for report: 0
🚀 Solo Findings: 0
🌟 Selected for report: IllIllI
Also found by: 0v3rf10w, 0x1f8b, 0x4non, 0xDjango, 0xf15ers, 0xkatana, 242, Dravee, GimelSec, MaratCerby, Tadashi, TrungOre, WatchPug, defsec, fatherOfBlocks, gzeon, hake, horsefacts, joestakey, miguelmtzinf, pauliax, pedroais, peritoflores, rotcivegaf, simon135, slywaters, tabish, throttle, z3s
28.3489 USDC - $28.35
No need to use safemath library for solidity 0.8.4+ as the compiler itself now checks for overflow/underflow, hence results in lot of gas savings
prefer != instead of > for unsigned integer, saves gas
https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L179
https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L233
uint256 should be preferred, not against readability of code https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L145 https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L136
no need to increase or decrease allowance if it's approved for max limit,results in lot of gas savings Similar optimizations are used in ERC20 tokens like WETH, The Wrapped Ether (WETH) ERC-20 contract does not update the allowance if it is the max uint.
https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L296 https://github.com/pooltogether/aave-v3-yield-source/blob/e63d1b0e396a5bce89f093630c282ca1c6627e44/contracts/AaveV3YieldSource.sol#L315
#0 - PierrickGT
2022-05-02T22:30:10Z
Gas1: PR: https://github.com/pooltogether/aave-v3-yield-source/pull/5
Gas2: We would only save 3 in gas for each function call, which is not worth the loss in legibility of our code.
Gas3:
The Aave supply function accept a uint16 for the referral code so we need to store it in a uint16: https://docs.aave.com/developers/core-contracts/pool#supply
Decimals are stored in a uint8 in the OpenZeppelin contract, so if we want to overwrite the default value, we need to store it in a uint8: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/14ca3aeb798d9b9be31df86ae7ef8b8f760caa4c/contracts/token/ERC20/ERC20.sol#L87
Gas4: Not really a gas optimization. We can check the allowance off-chain before calling these functions, so we can avoid spending ETH for a transaction.